So dear Jacob informs me as he comes in from recess, "I'm wearing my jammies under my clothes today."
Thinking it was because of the 5 degree-freeze-your-nose-hairs weather we've been having in Layton, I asked, "Are you wearing your jammies to keep you warmer?"
"No. It's in case I get tired."
Makes sense. You'd want to be prepared should the sleepy bug hit you. I might start wearing my jammies to church.